New formula quantifies serious hazards to young children left in hot cars

A mathematical model developed by Robert Brown, Texas A&M professor of landscape architecture, was used in a highly publicized study quantifying the time it takes for young children to become dangerously hot when they are accidentally left in the back seat of a sweltering car.

The study, led by Jennifer Vanos, a member at the University of California, San Diego faculty, found that approximately 80 minutes trapped in a sunny car is enough to kill a child. In a shaded vehicle, it takes slightly under two hours for a two-year-old's body to reach a lethal temperature.

Release of the findings created a nationwide media buzz, which Vanos hopes will go far toward reducing the grim toll of hot car-related fatalities

"I'm hoping the publicity can invoke additional awareness of the issue, support technological solutions from car and device manufacturers, and advance new policies that give people legal immunity if they need to save children and pets trapped in hot vehicles," she said.

Approximately 37 children die each year from pediatric vehicular hyperthermia, in which the body warms to more than 104 degrees and cannot cool down. Also, in the last 20 years, approximately 750 children in the U.S. have suffered from heatstroke after they were left unattended in a car.

Brown's co-developed the Comfort Formula, or COMFA, which informed Vanos' study, in 1981 as part of his Ph.D. studies. It contains a series of equations combining climate factors, such as temperature and humidity, with physiological data and other factors, to estimate thermal comfort and potential heat stress.

Vanos is a member of Brown's Microclimatic Design Research Group, an interdisciplinary cohort of scholars who study how cities can be more comfortable by learning how design affects temperature, solar radiation, wind, and other environmental factors in small areas.

The group's findings are especially relevant, said Brown, in light of climate change and ever-increasing use of impermeable, dry surfaces that cause urban areas to become warmer than their rural surroundings.